Workshops and Short Courses

Filters and multiplexers are key building blocks in science, navigation, and earth observation and telecommunication applications. Satellite systems are in constant evolution to answer to new and changing needs in terms of throughput, coverage, flexibility, RF performances ... The following bullet points offer an overview of some of the different approaches to respond to the new system requirement. Dielectric filters – already extensively used for low power narrow channels up to 20 GHz, are now being applied for medium/high power levels and higher frequencies too. Additionally, new topologies based on dielectric materials are helping to get more compactness for lower frequencies thanks to the very good quality of new dielectric materials. Reconfigurable filters – Reconfigurable filters are commonly found in satellite system studies targeting traffic flexibility between beams or reconfiguration of the channels due to the orbit reallocation of the satellite. Advances in reconfigurable filters able to cope with demanding specs and high power have been done in the last years. High power handling – new developments have been done to cover the demand of RF/microwave filters withstanding higher power. Solutions based on new materials, novel mode solutions and new synthesis approaches have been already presented in the last years. New manufacturing methods and materials – this topic is being intensively discussed nowadays. The application of new manufacturing approaches based on the additional of material supposes a breakthrough in the current RF/microwave filter design. Additional design margins can be explored together with co-simulation including electrical, mechanical and thermal issues. Additionally, new materials are being developed where, based on doping strategies, the material can be customized for electrical, mechanical and thermal perspective. Programme 13:50 14:00 Welcome 14:00 14:30 Current and future requirements for RF/microwave filters Petronilo Martin-Iglesias, ESA ESTEC, Noordwijk, The Netherlands  Abstract 14:30 15:00 Reconfigurable Waveguide Filter with Variable Bandwidth and Center Frequency Christian Arnold, TESAT  Abstract 15:00 15:30 Reconfigurable Filtering Sections for Space Applications Nikolas Sidiropoulos, Space Engineering, Italy  Abstract 15:30 16:10 Coffee Break 16:10 16:40 New channels solutions in COMDEV : high power ku-band dielectric OMUX channel and superQ Ka-band OMUX channel Ming Yu, COMDEV, Canada  Abstract 16:40 17:10 Compact Filters and Diplers for Space Applications Based On TM Dielectric Resonator Luca Pelliccia, RF microtech, Italy  Abstract 17:10 17:40 Low Q, high performances IMUX channel Joan O'Callaghan and Luis Javier Rogla, UPC / Thales Alenia Space, Spain  Abstract 17:40 17:50 Discussion WORKSHOPS AND SHORT COURSES 13:50 14:00 Current and future requirements for RF/microwave filters Petronilo Martin-Iglesias, Telespazio Vega for ESA, UK Abstract This presentation will work as an introduction for the presentations integrated in this workshop. An overview of current and future system requirements for passive hardware will be performed in this presentation. The need of more compact, high power handling capabilities, bandwidth flexibility will be presented and discussed based on some system architectures. The discussion will be mostly dedicated to telecommunication satellite systems due to the high number of filters integrated on this type of payloads. Broadcast and broadband will be analysed and the derived requirements for the filters will be presented. Additionally, the review of other systems/subsystems such as TT&C and mobile satellite systems will be performed. 14:30 15:00 Reconfigurable Waveguide Filter with Variable Bandwidth and Center Frequency Christian Arnold, TESAT Abstract This talk presents a center frequency and bandwidth reconfiguration mechanism for waveguide microwave bandpass filters. The filters are designed to be used in the output section of a satellite communication system. While the center frequency of a bandpass filter can be tuned by changing the lengths of the filter resonators, the coupling irises as practical realizations of the impedance inverters cannot easily be adapted to a new value. The novel approach chosen in this paper is to replace the impedance inverters by a novel type of coupling structure. This coupling structure allows adjustment of the coupling by changing the length of a transmission line, which is equivalent to changing the resonant frequency of a coupling resonator. Design equations are presented to transform an impedance inverter into the proposed coupling structure. A synthesis procedure for bandwidth reconfigurable filters is proposed. The feasibility of coupling adaptation is proven based on a full-wave model of the coupling structure. The synthesis process is applied to a four-pole Chebyshev sidewall-coupled circular waveguide filter with 54and 72-MHz bandwidth settings. The filter is built up and measured. The measured results prove that the filter can be tuned to both bandwidths over a center frequency range of 200 MHz with excellent return loss and insertion loss. 15:00 15:30 Reconfigurable Filtering Sections for Space Applications Nikolas Sidiropoulos, Space Engineering, Italy Abstract The flexibility of future satellite systems in terms of resources usage and allocation and the development of the relative hardware are currently of the most interesting research topics for space. A demonstration of this are the several studies at both system and component level, on flexible payloads and reconfigurable HW, such as amplifiers, filters, antennas, etc. that are undergoing in Europe. In this context, the flexibility in multiplexer devices is of high interest, since it is currently the bottleneck for flexible payloads with adjustable bandwidth. The advantages of having the capability to tune in-orbit the input/output filters in terms of bandwidth and frequency, are multiple. Up today, when some degree of reconfigurability is desired, payload engineers are obliged to adopt switched multiplexer solutions that increase the overall IMUX/OMUX mass, complexity and costs. In such scenarios, the utilization of reconfigurable IMUX/OMUX would allow substantial reduction of both mass and costs. Ideally one reconfigurable IMUX and OMUX design could fit to all payloads operating in a certain band. Concepts for reconfigurable multiplexers exist in literature but known solutions have a large penalty of dissipation losses, which make performance of current solutions unacceptable for use in space. The main problem, from the RF point of view, is the mutual interaction between adjacent channels of single manifold multiplexers. Novel concepts such as a dual manifold multiplexer or a revisited version of hybrid coupler multiplexers are investigated to overcome today’s limitations and provide the needed break-through. The problem is more complex considering the constrains coming from the high-power handling requirements, that reach levels above 250 W per channel up to Ka-band, while reliability of the reconfiguration concept is a critical aspect for space. The associated reconfigurable filters need to provide flexibility in terms of frequency and bandwidth tuning, with minimum increase of mass and envelope wrt fixed filters. Flexible filtering configurations can be achieved by different approaches, for example a) with a switchable bank of individual filters, b) by means of a switchable bank of individual cavities per filter, or c) by implementing a single reconfigurable filter. The last approach has advantages for in-orbit applications, since it provides optimum trade-off between RF performances, tuneability and mass/envelope. In general and without considering qualification aspects and suitability for space applications, most of the approaches proposed in literature, including many patents, concern filters that allow center frequency reconfiguration. The issue of bandwidth reconfiguration, has also been studied but at a smaller degree, being in principle more difficult and complex to achieve. A combination of pseudo-high-pass and pseudo-low-pass filters provides a viable solution to this problem. For what concerns the reconfiguration concept, a mechanical tuning approach, by means of high precision actuator can be applied. The miniaturization of the geometry imposes very stringent requirements in terms of positioning accuracy (of the order few microns) for the tuning mechanism. The actuator needs to be operated in closed loop. Space Engineering and NOW Srl are currently investigating such configuration that is the first step toward the development of such reconfigurable channel filters for IMUX devices. The requirements of the filter, in terms of in-band amplitude flatness, group delay variation and near-band attenuation are close to those typically imposed to Ku-Band IMUX channel filters. 16:10 16:40 New channels solutions in COMDEV : high power ku-band dielectric OMUX channel and superQ Ka-band